1. Field of the Invention
The present invention relates to a radiation imaging system for acquiring a radiation image and an operation method thereof, and a radiation image detecting device and a storage medium storing an operation program therefor.
2. Description Related to the Prior Art
In a medical field, an X-ray imaging system using radiation such as X-rays is known, for example. The X-ray imaging system includes an X-ray generating apparatus for generating X-rays and an X-ray imaging apparatus for acquiring an X-ray image of an object (i.e. patient) from the X-rays having passed through the object. The X-ray generating apparatus includes an X-ray source for irradiating the X-rays to the object, a source controller for controlling the operation of the X-ray source, and an irradiation switch for inputting a command to start X-ray irradiation to the source controller. The X-ray imaging apparatus includes an X-ray image detecting device for detecting the X-ray image by converting the X-rays having passed through each part of the object into an electrical signal, and a console for controlling the operation of the X-ray image detecting device and storing and displaying the X-ray image.
An X-ray imaging apparatus using an X-ray image detecting device for electronically detecting an X-ray image has been widely spread instead of an X-ray image recording apparatus using an X-ray film or an imaging plate (IP) cassette. The X-ray image detecting device has a sensor panel that is also referred to as a flat panel detector (FPD).
The sensor panel has an imaging area in which pixels for accumulating signal charges corresponding to a dose of incident X-rays are arranged in a matrix form. Each of the pixels has a photoelectric converter for generating electric charges and accumulating the generated electric charges, and a switching element such as a thin film transistor (TFT). The sensor panel reads out the signal charges accumulated in the photoelectric converter of each of the pixels through a signal line disposed for each column of the pixels to a signal processing circuit upon turning-on of the switching element. Then, the signal charges are converted into a voltage signal in the signal processing circuit. Thereby, an X-ray image is electronically detected. The sensor panel performs an accumulation operation for accumulating the signal charges in each of the pixels, and a readout operation for reading out the accumulated signal charges through the switching element such as the TFT to the signal processing circuit.
As disclosed in United States Patent Application Publication No. 2012/132820 (corresponding to Japanese Patent Laid-Open Publication No. 2012-129984) and Japanese Patent Laid-Open Publication No. 2012-135588, in the case of acquiring one sheet of X-ray image, for example, a dose necessary for acquiring one sheet of X-ray image is set in accordance with a body part to be imaged and a body frame of an object in an X-ray generating apparatus. Then, when an irradiation switch is manipulated once by an operator such as a radiation technologist, the X-rays at the set dose are irradiated from the X-ray generating apparatus. In synchronization with the irradiation timing of the X-rays by the X-ray generating apparatus, the sensor panel turns off the switching element and performs an accumulation operation. Upon completion of the X-ray irradiation, the sensor panel turns on the switching element, and reads out the signal charges accumulated in the pixel to a signal processing circuit. Such a readout operation is performed for every pixel. After the readout operation, the sensor panel converts the signal charges into digital data by the signal processing circuit, so as to produce an X-ray image for diagnosis containing information of all pixels. The produced X-ray image for diagnosis is transmitted from the sensor panel to the console, and displayed on a monitor of the console.
An X-ray image detecting device disclosed in United States Patent Application Publication No. 2012/132820 and Japanese Patent Laid-Open Publication No. 2012-135588 includes a preview image producing device for subjecting the X-ray image for diagnosis to thinning processing so as to produce a preview image having a small amount of data. The produced preview image is transmitted to the console prior to transmission of the X-ray image for diagnosis. The preview image has a data amount smaller than that of the X-ray image for diagnosis, and therefore it takes a short period of time to transmit the preview image to the console. After the X-ray imaging, an operator measures success and failure of the X-ray imaging. For example, the operator checks whether or not the positioning of the object was appropriate on the monitor of the console. As disclosed in United States Patent Application Publication No. 2012/132820 and Japanese Patent Laid-Open Publication No. 2012-135588, in the case where the preview image is transmitted prior to transmission of the X-ray image for diagnosis, it becomes possible to measure success and failure of the X-ray imaging promptly.
According to United States Patent Application Publication No. 2012/132820 and Japanese Patent Laid-Open Publication No. 2012-135588, a series of processing including production, transmission, and display of the preview image is started after the X-ray irradiation necessary for acquiring one sheet of X-ray image is completed. The data transmission time to the console is shortened by producing the preview image having a small amount of data. However, since the above-described series of processing is started after the completion of the X-ray irradiation necessary for acquiring one sheet of X-ray image, it is impossible to make the time taken from the completion of the X-ray irradiation to the display of the preview image shorter than the time taken for the above-described series of processing. Although the waiting time before the preview image is displayed is a small amount of time, an operator who is required to perform an operation speedily feels like that the waiting time is long. Therefore, it has been desired strongly to decrease the time required for displaying the preview image. Consequently, it has been desired to take measures to display the preview image more promptly.